Motor-starting rheostat.



No. 829,151. PATENTBD AUG. 21, 1906. J. L. HALL & w. c. YATES.

MOTOR STARTING RHBOSTAT.

APPLIUATIOH FILED we. 23. 14:04.

Witnesses. Inventors. John L.||a|l.

M Willie C.Yaes.

1 4 y MW ,us rrED sTA rEs PATENT orrron.

JOHN L. HALL AND WILLIAM O. YATES, OF SCHENECTADY, NEW YORK, ASSIGNOR TOGENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

MOTOR-STARTING RHEOSTAT- 10. 829,151. Specification of Letters iatent.

Application filed A gust 23,1904. Serial No. 221,817.

Patented Aug. 21, 1906.v

motor and is divided. into a plurality of seclo (1,7 Z whom it mayconcern: tions by leads running to contacts 6, 7, and 8 1 Be it knownthat we, JOHN L. HALL and of a corresponding number of electromagnet- 55 WILLIAM C. Yarns, citizens of the United ically-actuated switches,each of which when States, residing at Schenectady, county of closedshort-circuits one section of the re- 5 Schenectady, State of New. York,have insistance. In the present instance we have vented certain new anduseful Improveshown three short-circuiting switches and merits inMotor-Starting Rheostats, of which the resistance 5, divided into threesections, the following is a specification. though any other number maybe provided,

This invention relates to motor-starting if desired. Each of theseswitches has an aclo rheostats, and particularly to rheostats ofmating-winding 9, 10, and 11, a retainingthis type arranged forautomatic operation winding 12, 13, and 14, and a pivoted armaon closureof the circuit through the motor. ture 15, 16, and 17, respectively, andeach of 6 5 Our invention consists of the combination these armatures isprovided with a contact of anelectric motor, a resistance in circuitwhich whenth switch is closed engages one 15 therewith, and a pluralityof electromagnetof the stationary contacts 6, Z, and 8. Eachically-actuated switches arranged to be operof the armatures 15, 16, and17 is connected ated automatically in succession to shortby a flexibleconductor to a binding post i8, circuit sections of the resistance. Inorder and each of these binding-posts is connec ed to avoid the dangerof injury to the coils of to the ends of the sections of the resistance5,

so the motor by the admission of an excessive as shown. Each armaturealso carries a pin current thereto while it is coming up to orprojection 19, which when the switr'his op speed, we arrange theoperation of these elecerated engages the movable arm of a smalltromagneticallyac'tuated switches to be deswitch 20 and throws thislatter switch to the pendent on the counter electromotive force 0 en,position. The actuating-winding 9 of 5 of the motor. T he power requiredto oper t e first switch is connected in circuit be ate these switchesis greatly in excess of that tween the point 21 on the positive wire andnecessary to hold them in the closed osition, the stationary contact ofthe small switch 20, So and for'this reason we provide eacii switch andthe movable contact of this switch is with an actuating-coil and aretaining-coil, connected to the negative side of the arma- 301: andarrange devices to open the circuit of the ture at the point 22. Theactuatingwindactuating-windin'gswhen the switches have ings 10 and 11 ofthe other two switches are been thrown to the closed osition. The resimilarly connected between the points 24 ltaining-coils of the severeswitches remain and 25 on the positive wire and the point 22.ipermanently in circuit while the motor is It will thus be seen that theactuating-wind- 5 5 running and are preferably connected in seings ofthe several switches are in shunt to' ries across the lines. thearmature-3 of the motor, and the opera- The novel features of ourinvention will be tion of the switches will therefore be depend- 9odefinitely indicated in the claims appended ent upon the counterelectromotive force of hereto. The details of construction and the themotor. In order that the switches may 4 mode of operation of ourimproved motoroperate successively, any of the wellknown.

starting, rheostat will be better understood expedients may be em loyedbut in order to by reference to the following description, permit theuse of similar coils on all of the 5 ,taken in connection with theaccompanying switches we prefer to obtain the successive drawing, whichshows in diagram, the preoperation by varying the air-gap between the 45ferred embodiment of our invention. contacts carried by the armatures15, 16, and

In the drawing, 1 an 2 indicate positive 17 and the stationary contacts6, 7, and.8. and negative mains lea ing-from any suit- "This may readilybe accomplished by the ad able source of supply of electric energy. 3justable stops 26, mounted by threaded conindicates the armature, and 4the field, of an nections in projections on the magnets and 5 electricmotor which is to be run by current cooperating with extensions on thearmatures from themains 1 and 2. Aresistance 5 is con to limit themovement thereof.- a The retainn'ected inisei ies with the armature 3 ofthe ing-windings 12, 13, and 14 of the electror05 magnetically actuatedswitches are connected in series across the lines, one end of the wnding 12 being connected to the positive wire at 27 and the opposite endof winding 14 being connected to the lead running from the contact 8 tothe negative side of the armature 3 and the resistance 5.

The operation of the motor-starting rheostat wil be understood from theforegoing description. Current is admitted to the motor b the closure ofthe line-switch 28, which may e mounted at any convenient point'distautfrom the motor and which closes circuit through the armature 3 andresistance 5 in series, through the shunt-field 4, and through theretaining-coils 12, 13, and 14 in series. When circuit is first closed,the resistance 5 prevents dangerous overloading of the .motor-armature3, and the drop in voltage across the armature is so small that thecurrent which is shunted through the actuatingcoils 9, 10, and 11 of theswitches/is insufficient to operate the switches; but as the motor comesup to speed the counter electromotive force, and hence the drop acrossthe armature, increases, causing more and more current to flow throughthese actuating-coils. After a predetermined rise in the counterelectromotive force the operating-coil 9 of the first switch energizesthe magnet with sufficient strength to attract armature 15, which whenin the closed position engages the stationary contact 6, and thus closesa short-circuit around one section of the resistance 5. The movement ofarmature 15 also causes the pin 19 to open the switch 20, thus openingthe circuit of the coil 9. The armature 15 is, however, held in theclosed position by the retaining-winding 12, which, as heretoforeexplained, is connected in series with the retaming-windings of theother switches across the lines. The short-circuiting of one section ofresistance 5 permits more current to flow through the motor-armature,and the motor therefore speeds u ,causing an additional rise in thecounter e ectromotive force. When the drop across the motor'armature,due to this rise in the counter electromotive force, has reached adefinite amount, the armature 16 of the second switch, the air-gap ofwhich is somewhat greater than that of the first switch, will beattracted, thus cutting out another section of the resistance 5, and, asin the case of the first switch, the actu atingwinding will beopen-circuited and the armature held in the closed position by theretaining-winding 13. The third SWIlJCh has the greatest air-ga and is oerated in a similar manner after t e motor as speeded up still further.When the motor has come up to normal speed, theresistance 5 is all cutout, the actuating-windings of the several switches are allopen-circuited, and the only loss of en-, ergy is in theretaining-windings 12, 13, and 14, and this loss is very small, sinceonly a small amount of power isrequired to hold the switches in theclosed position. When the line-switch 28 is opened, the circuits throughthe motor are opened and also the circuit through the retaining-windings12, 13, and 14, and the armatures 15, 16, and 17 drop by gravity or arereturned in any suitable manner to the ositions illustrated in thedrawing, so that al parts are in readiness for a repetition of the oeration.

What we 0 aim as new, and desire to secure by Letters Patent of theUnited States, is-

1. In combination, an electric motor, a plurality of switches forvarying the speed of the motor, an actuatin g-coil on each swltch foroperating the same, means associated with each switch for deenergizingits actuatingcoil upon the operation of the switch, and means forholding each switch in the operated osition.

2. n combination, an electric motor a plurality of switches for varyingthe speed of the motor, an actuating-coi u on each switch for operatingthe same, auxiliary contacts associated with each switch for denergizingits actuating-coil upon the opt-ration of the switch, and means forholding each switch in the operated position and maintaining thedcnergized condition of the actuating-coil.

3. In combination, an electric motor, a plurality of normally openswitches for varymg the speed of the motor, an actuating-coil on eachswitch for operating the same, normally closed contacts associated witheach of the switches and arranged in the circuits of their respectiveactuating-coils, means for o ening each of said auxiliary contacts upontl ie closing of the res ective switches, and means for holding eaciiswitch in the closed position and the contact in open position.

4. In combination, a "motor a plurality of switches for varying the seed of the motor, an actuating-coil for eac switch, separate circuitsfor energizing said coils, means for opening each of said circuits uplonthe operation of the corresponding switc and electromagnetic means formaintaining said circuits open and the switches in operated position.

5. In combination, an electric motor, a plurality of switches forvarying the speed of the motor an actuating-coil on each switch foroperatin the same, said switches being so connecte and arranged that theswitches operate in automatic succession as the counter electromotiveforce of the motor increases, means for deenergizing eachof said coilsduring the period the corresponding switch remains in its operatedposition, and electromagnetic maintaining means for said switches.

6. In combination, an electric motor, a plurality of switches arrangedto operate in automatic succession to vary the speed oi the motor, anactuating-coil on each switch for operating the same,"separate circuitsfor en- ITO ergizingeach of said coils, means for opening each 0 saidcircuits upon the operation 0 the corresponding switch, and electromag-;netic means for maintaining said circuits and .the switches in operatedposition.

7. In combination, an electric motor, a resistance switches for cuttingsaid resistance into and ing-coil on each switch for operating the same,the several switches being arranged to o 'erate inautomatic successionto cut out t e resistance, means associated with each switch fordenergizing its actuating-coil upon the operation of the switch, and-means for maintalning each switch in its operated position and eachcoil in its denergized condition. g

8. In combination, a motor,-a resistance, a

- plurality of switches for cutting said resist- -ance into and out ofthe motor circuit, an

actuating coil on each switch for operating the same, a soil on eachswitch for maintaining the switch in the operated position and 7 meansassociated with each switchjfor energizlng its actuating-coil durin theperiod the switch remains in its operate position.

9. In combination, a motor, a resistance, electromagnetically operatedswitches for cutting said resistance into and out of the motor-circuit,an actuating-coil on each switch for operating the same, means fordeenergizing each actuating-coil during the eriod the correspondingswitch remains in its oplerated position, and a coil on each switc formaintaining it in its operated poout of the motor-circuit, an actuatsition, said maintaining-coils being connected in series across theline. a

10. Inconibination, a motor, a resistance, electrgmagnetically-operatedswitches for cutting the resistance into and'out of the motor-circuit,said switches having armatures'arrang'ed with'v'arying air-gaps,actuatingcoilson the switches connected in shunt to the motor-annature,maintaining- "coils on the switches, and means for opening the circuitofeach ofsaid actuating-coils during'the remains in t eoperatedposition. a 11. In combination, a motor, a resistance in circuittherewith, electromagnetical actuated switches ifor cutting theresistancei into and out of the motor-circuit, actuating- JOHN L. HALL.WILLIAM C. YATES.

Witnesses BENJAMIN B. HULL, HELEN ORFORD.

period the corresponding switch

